1. Field of the Invention
The present invention relates to a method and an apparatus for accessing an initial channel, and more particularly, to a method and an apparatus for accessing an initial channel by a station (STA).
2. Related Art
In recent years, an evolution direction of a wireless LAN technique has been largely progressed into three directions. As an effort for further increasing a transmission speed on an extension line of the wireless LAN evolution direction in the related art, IEEE (institute of electrical and electronic engineers) 802.11ac and IEEE 802.11ad are provided. The IEEE 802.11ad is a wireless LAN technique using a 60 GHz band. Further, a wideband wireless LAN using a frequency band less than 1 GHz to enable wideband transmission distantatively rather than the wireless LAN in the related art has been come to the fore in recent years and includes IEEE 802.11af using a TV white space (TVWS) band and IEEE 802.11ah using a 900 MHz band. The wideband LANs mainly aim at extension of an extended range Wi-Fi service in addition to a smart grid and a wideband sensor network. Further, a wireless LAN medium access control (MAC) technique in the related art has a problem that an initial link setup time is significantly lengthened in some cases. An IEEE 802.11ai standardization activity has been recently in active progress in order for an STA to rapidly access an AP by solving the problem.
The standardization activity of the IEEE 802.11ai as an MAC technique that handles a rapid authentication procedure in order to epochally save an initial set-up and association time of the wireless LAN has been started as a legal task group in January 2011. In order to enable the rapid access procedure, the IEEE 802.11ai has discussed procedure simplification in regions such as AP discovery, network discovery, time synchronization function (TSF) synchronization, authentication and association, procedure merge with a higher layer, and the like. Among them, ideas including procedure merge using piggyback of a dynamic host configuration protocol (DHCP), optimization of a full extensible authentication protocol (EAP) using a concurrent IP, efficient selective access point (AP) scanning, and the like have been actively discussed.